Hand-held power tools are divided into three categories:
1. Class I tools. In addition to the basic insulation, zero protection is also used to prevent electric shock. Class I tools are metal shell, the power supply part has insulation performance, suitable for dry places;
2. Class II tools. The tool itself has double insulation or reinforced insulation, and no protective grounding measures are taken; Class II tools not only the power part has insulation performance, but also the shell is an insulator, that is, it has double insulation performance, and the nameplate of the tool is marked with the word "back", which is suitable for humid workplaces;
3. Class III tools. Powered by a safe ultra-low voltage power supply, no voltage higher than the safe ultra-low voltage is generated inside the tool; The tool is powered by a safe voltage supply and is suitable for work in particularly wet workplaces and metal containers.
Hand power tool
Handheld power tools refer to portable power tools that can be operated directly by hand without other auxiliary devices. For example, electric drills, curve saws, miter saws, wrenches, electric welding pliers commonly used in construction.
The safety hazards of hand-held power tools mainly exist in electrical appliances, which are prone to electric shock accidents:
1. The protection zero and two-stage leakage protector is not set, or the protection fails.
2. The insulation layer of power tools is damaged and leakage occurs.
3. The power cable and switch box do not meet the requirements.
4. Workers violate operating regulations or do not wear insulation supplies as required.
